Various kinds of doormats have been used bacause a room was stained with muck adhered to the outsole of shoes in the case of entering a room with stained shoes.
Up to date, metallic coil spring bonded in a state of sheet or pile has been used as a doormat. Recently, the synthetic resin was extruded in a fine fiber, and then the fibers got tangled with each other irregularly in a state of coil, the sheet obtained was used as doormat. Among them, the doormat made of metallic coil spring easily eliminated muck adhered to the outsole of shoes. Such metallic doormat, however, has a disadvantage that it was difficult to shake fine muck from boots since scrapable effect was reduced by crushing of matallic coil spring in using doormat. Other disadvantage was that it had poor feeling by hardness. Also, the doormat made of pile had disadvantages that it was inconvenient in wetting and therefore it had to be dry, furthermore, it could hardly eliminate muck. Also, although the third doormat eliminated well muck adhered to the outsole of shoes, which muck in aperture of coil irregularly tangled was hardly eliminated.